Description
The A8439 is a highly integrated IC that charges photoflash capacitors for digital and film cameras. An integrated MOSFET switch drives the transformer in a flyback topology. It also features an integrated IGBT driver that facilitates the flash discharge function and saves board space.
The CHARGE pin enables the A8439 and starts the charging of the output capacitor. When the designated output voltage is reached, the A8439 stops the charging until the CHARGE pin is toggled again. Pulling the CHARGE pin low stops the charging. The DONE pin is an open-drain indicator of when the designated output voltage is reached.
The peak current limit can be adjusted to eight different levels between 270 mA to 1.4 A, by clocking the CHARGE pin. This allows the user to operate the flash even at low battery voltages.
The A8439 can be used with two Alkaline/NiMH/ NiCAD or one single-cell Li+ battery connected to the transformer primary. Connect the VIN pin to a 3.0 to 5.5 V supply, which can be either the system rail or the Li+ battery, if used.
The A8439 is available in a very low profile (0.75 mm) 10-terminal 3×3 mm MLP/TDFN package, making it ideal for space-constrained applications. It is lead (Pb) free, with 100% matte-tin leadframe plating.
The 8439 is part of a product family that includes the 8436and 8438.
Functional Block Diagram
Features
- Power with 1 Li+ or 2 Alkaline/NiMH/NiCAD batteries
- Adjustable output voltage
- Autorefresh
- >75% efficiency
- Eight-level, digitally-programmable current limit
- Charge complete indication
- Integrated IGBT driver with trigger
- No primary-side Schottky diode needed
- Low-profile package (0.75 mm nominal height)
Applications
- Digital camera flash
- Film camera flash
- Cell phone flash
- Emergency strobe light
source：ShenZhen henlito electronic co.,ltd.
web:www.henlito.com
